Lubricants



- 1 a... Apr. 11, 1950 I UNITED STATES PATENT OFF! LUBRICANTS Leonard A.Mattano and Lawson W. mond, Ind., assignors to Standard liiixon, Ham-Oil Company,

Chicago, 111., a corporation of Indiana No Drawing. Application 7 SerialNo. 83,7

March to, 1949, 57 p 11 Claims. (Cl. 252-483) The present inventionrelates ,to compositions possessing'corrosion and/or rust preventiveproperties. More particularly, the inventionrelates to oleaginouscompositions which possess corrosion and/or rust inhibiting properties,particularly when such compositions are used in systems prevention orinhibition of such corrosion or rusting is highly important. Similarproblems exist in the lubrication of certain types of marine engines.

The present invention is also applicable to anti-rust or slushingcompositions for the protection of metals against corrosion and/orrusting. Metallic products, prior to storage, are coated with ananti-rust material to prevent corrosion and/or' rusting while'instorage. Similarly, fabricated metallic articles and finished orsemi-finished metallic stocks destined for shipment by rail or by wateror to be stored, are protected against attack by moisture by coatingsuch materials with anti-rust or slushing compounds.

It is an object of the present invention to provide an improvedcomposition which will effectively inhibit or prevent thecorrosionand/or rusting of metallic surfaces.

Another object of the invention is to provide an improved compositionwhich will efiectively inhibit or prevent the rusting and/or corrosionof metallic surfaces of equipment which come in contact with water orsteam.

A further object of the invention is to provide a slushing compositionwhich will effectively inhibit or prevent the rusting and/or corrosionof metal surfaces.

Still another object of the invention is to pro- 'vide a lubricantcomposition which will efiectively inhibit or prevent the corrosionand/or rusting of metal surfaces of equipment employing such lubricant,particularly equipment in which water or steam may be present.

We have discovered that the foregoing objects can be attained byincorporating in organic compositions, particularly one containing amajor proportion of an oleaginous material, such asa natural orsynthetic hydrocarbon oil, a mineral oil, a vegetable, marine or animaloil, synthetic ester-type oils, or combinations thereof, a small amount,for example, from about 0.001% toabout 2%, and preferably from about0.002% to about 0.1% by weight, of a 1,3,4-tricarboxy-2-thiabutane havinthe general formula in which the substituents R, R and R" are selectedfrom the group consisting of hydrogen and an alkyl radical, and in whichat least one of the Rs is hydrogen and at least one of the Rs is analky] radical. At least one of the alkyl radicals should contain atleast 10 carbon atoms, and

.preferably from about 10 to about 16 carbon atoms.

Specific examples of compounds illustrative of compounds coming withinthe above general forinla are the following:

l-decylcarboxy-3,4-dicarboxy-2-thiabutanel-dodecylcarboxy-3,4-dicarboxyr2-thiabutane1-tetradecylcarboxy-3,4-dicarboxy-2-thiabutane1-cetylcarboxy-3,4-dicarboxy-2-thiabutane'1-octadecy1carboxy-3,4-dicarboxy-r2-thiabutane4-tetradecylcarboxy-1,3-dicarboxy-2-thiabutane3-cetylcarboxy-1,4-dicarboxy-2-thiabutane3,4-di-dodecylcarboxy-l-carboxy-Z-thiabutane It is not intended to implythat all esters of the herein-described type serve with identicalefllciency as anti-rust or anti-corrosion agents. While they are alleffective they will exhibit some variation depending upon the nature andseverity of the service to which they are subject, the nature of themetal to be protected, the relative solubility. of the ester in themedia which may be used for application of the ester to the metalsurface and the relative stability of the ester at the servicetemperature.

Members of the herein-described class of compounds can be readilyprepared by neutralizing maleic acid with an alkali metal hydroxide,such as sodium hydroxide, and adding to the neutralized product analcoholic solution of a thiogly- I aooaeor temperature until titrationwith iodine indicates that the addition is substantially complete. Theproduct is then acidified, preferably with an aqueous solution ofhydrochloric acid, the acidifled product extracted with a hydrocarbonsolvent, such as ether or other low-boiling solvent, and the extractrecovered by evaporation of the solvent. The preparation of'l-tetradecylcarboxy-3,4-dicarboxy-2-thiabutane, is given to illustratethe specific example of the method of preparation. Twenty-fivehundredths moles of maleic acid is neutralized with a sodium hydroxidesolution and an alcoholic solution of tetradecyl thioglycolate (0.25mole) added to the neutralized acid. The mixture is stirred at roomtemperature until titration of a small sample of the reaction productwith iodine indicates that the addition is substantially completed; thisusually requires five to six hours. then acidified with hydrochloricacid, extracted with ether, and the extract recovered by evaporation ofthe ether.

Although. the esters of 1,3,4-tricarboxy-2-thiabutane of the typedescribed herein can be suitably employed in organic compositions,particularly oleaginous compositions in general, to inhibit or preventrusting and/or corrosion, for

The mixture is 4 hibits rusting of the type above described. Tho

rust-inhibiting characteristic of turbine oils containing theseadditives is demonstrated by the following test: Three hundredmilliliters of the oil to be tested are placed in a 400 ml. liplessglass beaker and heated to about 140 F. in an oil bath and the oilstirred with a stirrer maintained at about 750 R. P. M. When thetemperature of the oil sample reaches about 140 F., a cleaned test stripof cold rolled steel is suspended in the oil and stirring continued forminutes to insure complete wetting of the steel specimen. Thirtymilliliters of distilled water are then carefully added by pouring itdown the side of the beaker. and stirring continued for forty-eighthours. At the end of this period the specimen is removed from thebeaker, washed with naphtha and visually inspected for the presence ofrust. The method of carrying out this test is fully described in A. S.T. M. Manual-1942, page 274, and identifled as A. S. T. M.:D665-42T.

Samples of a turbine oil base, namely a hydrocarbon oil having a SayboltUniversal viscosity at 100 F. of about 150 seconds containing smallamounts of various esters of 1,3,4-tricarboxy-2- thiabutanes weresubjected to the above test and the following results obtained:

TABLE I A. S. T. M. rust test Additive Concentration per cent) Esterl-dodecylcarboxy-3,4-dimrboxy-2-thiabutane: Dis- Moderate. None None.None. None.

tilled Water.

l-tetradecylcarboxy-IiAdicarboxy-2-thiabutane:

Distilled Water Moderate. Slight. None. Do.

Synthetic Sea Water Slight. Do.

to produce more highly refined turbine oils hav-.

ing improved sludging resistant and emulsification properties, thedesirable components of oils responsible for the wetting and thereforerustinhibiting qualities of the oil were removed by these refiningmethods and the stable oils produced became inferior with respect torust-inhiblting qualities. In steam turbines, rusting is usuallyencountered in the upper portions of oil reservoirs, and other parts ofthe system, caused by droplets of water coming in contact with the steelsurfaces and displacing the oil with which the surface was covered. Anoil will provide adequate protection against this rusting only if itwets the steel surfaces preferentially as compared with water. In thepresence of oils which provide no protection coating, the steel surfacesare attacked by water with the formation of ferric oxide and blackmagnetic oxide. As the rusting progresses these oxides scale off and maybe carried in suspension in the oil, often scoring bearings, pluggingoil lines and often causing faulty operation or sticking of delicategovernor parts. The need for non-rusting turbine oils is thereforegreat.

In accordance with the present invention the addition of small amountsof the herein-described thiabutanes to turbine oils effectively in- Inaddition to the A. S. T. M. rust test the inhibited oils were subjectedto the so-called Shell tenacity test. This test is carried out asfollows:

At the end of the A. S. T. M. D-665-42T test, described above, the steeltest specimen are removed from the oil, the oil is replaced withdistilled water and the same test specimen then suspended in the beaker.Stirring is then continued at about F. and the test specimen examinedperiodically for rusting.

The following samples were subjected to the above test and the resultsobtained tabulated in Table II:

Sample 1.Control (mineral turbine oil base stock of about S. S. U. at100 F.)

Sample 2.--Control+0.02% l-dodecylcarboxy- 3,4-dicarboxy-2-thiabutane.

Sample 3.Control-|-0.03% l-dodecylcarboxy- 3,4-dicarboxy-2-thiabutane.

Sample 4.Control+0.02% 1 tetradecylcarboxy-3,4-dicarboxy-Z-thiabutane.

Sample 5.Control+0.03% 1 tetradecylcarboxy-3,4-dicarboxy-2-thiabutane.

TABLE II 011 Sample 24 Hours 48 Hours Severe 2 Very Slight...

None None. 4 o. Do. 5 ..do Do.

While the herein-described esters are especially well adapted for usein'turbine'oil compositions,

they can be used in small proportions, namely up to about 2% or more, ifrequired, as anti-rust or anti-corrosion agents for metals, in a widevariety of media, illustrated by the following:

Motor fuels; for example, automobile or aviation gasolines, tractorfuels, Diesel engine fuels, alcohol-containing motor fuels; Lighting andheating fuels; kerosene, stove oils, stove and lighting naphthas,furnace oils, fuel oils;

"Solvent naphthas; cleaner naphthas, such as Stoddard solvent, Y. M. andP; naphthas, hydroformed naphthas;

Lubricating and dielectric oils, motor oils, Diesel oils, aviationengine oils, marine engine lubricants, ear oils, oil field machinerylubricants, icemachine oils, steam cylinder lubricants,;transmissionoils, soluble oils, textile oils, cutting oils, turbine oils, insulatingoils;

Lubricating greases, stable gel-like or solid dispersions of metal soapsin hydrocarbon oils; Protective coatings, slushing oils and greases inwhich part or all of the hydrocarbon oil may be replaced by metal soapsand/or waxes such as the ester-type waxes, mineral waxes such aspetrolatum and paraflin waxes, pitches, tars,

asphalt rosin.

The compositions, such as for example, the hydrocarbon oil compositions,in which the ester is used, can in addition contain V. I. improvers,

viscosity-increasing agents, bloom producing agents, extreme pressureagents, antioxidants, dyes, and antiknock agents, as the case may beprovided only that these additional agents do not enter into appreciablechemical reaction with the ester or precipitate it from the oils towhich it has been added.

N Thus, in turbine. oils, we can in addition to an ester, add anantioxidant such as the polyhydric phenols and their alkyl derivatives,for example,

I 3. A normally non-gaseous petroleum oil fraction containing from about0.001% to about 2% of a 1,3,4-tricarboxy-2-thiabutane having the generalformula in which the substituents R, R and R" are selected from thegroup consisting of hydrogen and an alkyl radical and in which at leastone of the Rs is hydrogen and at least one of the R's is an alkylradical having at least 10 carbon atoms.

4. A hydrocarbon oil containing from about I 0.001% to about 2% of a1,3,4-tricarbo1w-2- thiabutane having the general formula 0 in which thesubstituents R, R ,and R" are selected from the group consisting ofhydrogen and an alkyl radical and in which at least one of the Rs ishydrogen and at least one of the Rs is an alkyl radical having at least10 carbon cathechol, tertiary butyl catechol, octyl catechol,

etc. Other eilective antioxidants include betanaphthol, amylbeta-naphthol, octyl beta-' naphthol, lauryl beta-naphthol,alpha-naphthol, amyl alpha-naphthol, N-phenyl alpha-naphthyl-- a'mine,di-alpha-na'phthylamine, and the like.

The antioxidant may suitably'be. used in a proportion in the range ofabout 0.001% to about 0.5% (by weight) based on the oil.

we claim:

1.. An oleaginous material containing from about 0.001% to about 2% of a1,3,4-tricarboxy- 2-thiabutane having the general formula in=which thesubstituents R, R' and R' are selected from the group consisting ofhydrogen andan' alkyl radical and in which at least one of the Rsishydrogen and at least one of the Rs is an alkyl radical having at least10 carbon atoms. 2. An oil containing from about 000196 to about 2% of a1,3,4-tricarboxy-2-thiabutane having the general formula ooa (10cmIOOlv' in which the substituents R, R and R" are'tricarboxy-2-thiabutane.

atoms.

5. A hydrocarbon oil containing from about 10. A hydrocarbon oilcontaining 0.001% to about 2% of 1-'-cetylcarboxy-3,4-dicarboxy-2-thiabutane. I

11. A composition consisting essentially of a hydrocarbon oil and fromabout 0.001% to about 2% of a 1,3,4-tricarboxy-2-thiabutane having thegeneral formula v H H r n-( -JJ s-o-n (Boon (Boom $00K" in which thesubstituents R, R and R" are selected from the group consisting ofhydrogen and an alkyl radical and in which at least one of the Rs ishydrogen and at least one of the Rs is an alkyl radical having from 10to 16 carbonatoms.

LEONARD A. MA'I'I'ANO.

LAWSON W. MIXON.

REFERENCES CITED The following references are of record in the file ofthis patent: 1 i

selected from the group consisting of hydrogen and an allgyl radical andin which at least one o! the R's is hydrogen and at leastone of. the

R's is an alkyl radical having at least 10 carbon UNITED STATESPA'I'En'rs Number Name Date 2,371,143 Barnum Mar. 13, 1045 2,371,207Zublin Mar. '13, 1945 2,462,200 Kleinholz Feb. 22, 1949 2.474.604 WassonJune 28, 1949 from about Y

1. AN OLEAGINOUS MATERIAL CONTAINING FROM ABOUT 0.001% TO ABOUT 2% OF A1,3,4-TRICARBOXY2-THIABUTANE HAVING THE GENERAL FORMULA